Refrigerating machine



- March 30, 1943. cm. STEENSTRUP ,3 0

REFRIGERATING MACHINE Filed Jilly 7 1942 mg. l.

Inventor: Carl H. Steensmup,

His Attorney Patented Mar. .30, 1943 a Carl H. 'Steenstrup, Schenectady, N. Y., assignor toGeneral Electric Company, a corporation of New York Application July7, 1942,'S'er ial No. 449,979

' 8 Claims. (01. 62125) Myinvention relates to refrigerating machines and particularly to such machines which employ evaporators of the so-called secondary type..

It is an object of my invention tofprovide a refrigertaing machine including an improved arrangement for utilizing an evaporator of the secondary type.

It is another object of my invention to provide a refrigerating machine including a. primary evaporator and'a secondary evaporator and. an improved arrangement for controlling the operation of the secondary evaporator.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointedv out with particularity in the claims annexed to I and forming a part .of-this specification.

For a better understandingof my invention, referencemay be had to theaccompanying drawing in which Fig. 1 is a view of .a portion of :a refrigerator cabinetincluding the cooling compartment and provided with a refrigerating machine embodying my invention; Fig. 2 is antenlarged sectional view onthe line 2-2 of Fig. 1; and Fig. 3 is an enlarged sectional view of another portion of the evaporator shown in Fig. 1.

Briefly; the refrigerating machine shown on the'drawing comprises an insulated refrigerator cabinet provided with an inner metal liner defining a compartment to be cooled and a suitable insulated door for closing the compartment. The compartment is cooled by a primary evaporator of the flooded type arranged in the upper portion thereof, and it is further cooled by a secondary evaporator arranged on the outside of thelinen and secured in heat conducting relationship with the liner. Heat from the secondary evaporator is transferred to the primary evaporator by-an intermediate evaporator of the secondary type' which is removably secured both to the primary evaporator and to the liner in heat exchange with the condenser portion of the secondary evaporator. The primary evaporator is controlled by a temperature responsive device including a thermal element secured to the primary evaporator in the usual manner. A portion of the intermediate evaporator is also secured to the primary evaporator adjacent the thermal element of the control so that upon a sudden load demand on the secondary evaporator system warm vapor will flow to the vicinity of the control element and cause the refrigerating machine to operate the primary evaporator even though the temperature of the primary evaporator is-sufiiciently low to satisfy the control.

Referring now;to the drawing in Fig. 1, I have shown a portion of a domestic refrigerator in which the cooling compartment is located, the base portion in which the machinery compart- .ment is located being omittedas it forms no part of the present invention. The refrigerator comprises a thermallyinsulated cabinet l0 provided with a metal liner ll forminga cooling compartment and a door l2 for closing the cooling compartment. In the upp r Portion ofthe' cooling compartment and suspended from the top wall of the liner is arranged an evaporator l3. In order to provide additional cooling capacity in the lower portion of the compartment an evaptorator M of the secondary type is secured to the outside of. the liner ll within the insulated wall of the cabinet. In the form illustrated the evaporator l4 comprises a continuous conduit or duct, extending back and forth across the wallo'f the cooling compartment; the upper portion of the'conduit comprises the condensing section of the secondary evaporator; the lower ,portions comprise the evaporating section. Within the evaporator l4 there is provided a quantity of vaporizable liquid which partially fills the evaporator, the remaining space in the evaporator being .filled with vaporized refrigerant. During theoperation of the evaporator [4 liquid refrigerant in the evaporating sectionis vaporized by the absorption of heat; the vapor rises to the condensing section and is condensed and then returns to the evaporating section by, gravity.

The evaporator I3 is a-primary evaporator and is supplied with refrigerant from a suitable refrigerating machine in accordance withthe usual practice; this primary evaporator is of the flooded type and includes a liquid and vapor separating header l5 formed by indentations inthe sheet metal walls of the evaporator and a plurality of ducts or louvers I 6 communicating with the lower portion of the header l5 and maintained I! in the usual manner by operationv of the refrigerating machine, and the periods of operation are determined by a control [8 vhaving an adjusting knob I9. This control starts and stops the refrigerating machine in response to the tem'- perature of the evaporator as determined by a thermal bulb or element 20 clamped to. the upper' portion of the header l5 above the normal level of liquid refrigerant. The control l8 operates normally to maintain the evaporator ii! at temperatures suitable for the freezing of ice in the space defined by the evaporator walls. A suitable shelf 2|, only a portion of which is shown, may be arranged in the evaporator to provide additional freezing surface. In order to operate the secondary evaporator H by removing heat therefrom, an auxiliary or intermediate evaporator, also of the secondary type, indicated at 22 is secured in heat exchange relation with the upper or condensing portion of the evaporator H and. with a side wall of the evaporator 13 adjacent the liquid refrigerant containing louvers. A plurality of clamps 23 are provided on the liner to hold the evaporator 22 tightly against the lineradjacent the evaporator l4 as clearly indicated in Fig. 2 so that heat may readily be transferred through the metal liner from one of the conduits to the other, and a plurality of similar clamps 24 are provided on the side wall of the evaporator l3 to hold the upper or condenser portion of the evaporator 22 in heat exchange relation therewith. The intermediate evaporator 22 thus serves to conduct heat from ing the temperature throughout the primary evaporator.

The arrangement described above is particularly useful when the shelves or other obstructions are placed in the cooling compartment so that the lower portion of the compartment or cabinet is not cooled sufficiently by the normal operation vof the primary evaporator, in which case the secondary evaporator is relied on to carry a substantial portion of the load. This system will operate to provide adequate capacity of the secondary evaporator even though the the secondary evaporator It to the primary evaporator I3 without the necessity of having the secondary evaporator l4 extend through the liner H into contact with theevaporator'IS. Furthermore, by making the intermediate evaporator readily removable the'primary evaporator may be taken out for inspection or repair without in any way interfering with the secondary evaporator.

During the operation of the refrigerating machine it may happen that food or'other articles placed within the lower portion of the cooling compartment produce a sudden load demand requiring increased capacity of the evaporator I4 and it is desirable that the primary evaporator l3 be maintained in operation even though its temperature may be such thatit would not require operation of the refrigerating machine to maintain the primary evaporator within its required range of temperatures. Thereis, therefore, provided an arrangement responsive to the load demand of the secondary evaporator for causing the control [8 to operate and satisfy the load demand of the secondary evaporator even though it is not in operation .at the time to satisfy a load demand on'the primary evaporator. In the arrangement illustrated and shown in detail in Fig. 3, a vapor riser or conduit 25 is connected in communication with the topmost coil of the intermediate evaporator 22 and extends upwardly into thermal contact with the control element or bulb 2D. Whenever there is an increased load demand on the secondary evaporator the refrigerant within the intermediate evaporator 22 which is vaporized rises and increases the temperature within the riser 25. This increase in temperature is immediately felt by the control bulb 20 which responds to start operation or to insure continued operation of the evaporator I3 to satisfy the demand on the secondary evaporator. The primary evaporator is, therefore, conditioned to operate at a sufficiently low temperature to transfer the heat from the secondary evaporator through the intermediate evaporator to the refrigerating machine as rapidly as possible. The operation of the riser 25 makes the increased load demand immediately effective in modifying the operation of the control without the necessity of increas food compartm nt should be divided in two separate compartments by a solid shelf or by the placing of articles on a grille shelf.

It will readily'be apparent from the foregoing that I have provided a simple and effective arrangement for transferring heat from a secondary evaporator to the primary evaporator and for insuring adequate cooling capacity of the secondary evaporator, and that the arrangement makes these advantages possible without the necessity of carrying the secondary evaporator through the metal liner of the cooling compartment.

While I have described my invention in connection with a household refrigerator, other applications will readily be apparent to those skilled in the art. I do not, therefore, desire my invention to be limited to the particular construction described and illustrated, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A refrigerating machine including a cabinet, a primary cooling element for cooling one portion of said cabinet, a secondary cooling element arranged in heat exchange relationship with said primary element for removing heat from another portion of said cabinet, means dependent upon the temperature of said primary element for controlling the operation thereof, and means dependent upon a load demand on said secondary element for modifying the operation of said temperature dependent means.

2. A refrigerating machine including a cabinet, a primary cooling element for cooling one portion of said cabinet, a secondary cooling element arranged in heat exchange relationship with said primary element for removing heat from another portion of said cabinet, means including a thermal element responsive to the temperature of said primary element for controlling the operation thereof, and means dependent upon an increased load demand on said secondary element to increase the temperature of said thermal element for modifying the operation of said controlling means to satisfy the increased load demand.

3. A refrigerating machine including a cabinet, a primary cooling element for cooling one portion of said cabinet, a secondary cooling element arranged in heat exchange relationship with said primary element for removing heat from another portion ofsaid cabinet, said secondary element having an evaporating section and a condensing section, and means including a thermal element responsive to the temperature of said primary element for controlling the operation thereof, said secondary element having a portion of its condensing section arranged in thermal contact with said thermal element whereby a predetermined load demand on said secondary element increases the temperature of said thermal element sufficiently to control the operation of said primary element to satisfy the increase in load demand.

4. 'A refrigeratingmachine including acabinet, a primary cooling element for cooling one portion of said cabinet. a secondary cooling element arranged in heat exchange relationship with said "primary element for removing heat from another portion of said'cabinet, said secondary element 7 having an evaporating section and a condensing section, means including a thermal element re sponsive' to the temperature of said primary element for controlling the operation thereof, and a riser in communication with the condensing section of said secondary element and having its upper end in thermal contact with said thermal element for actuating said controlling means 'upon the occurrence of a predetermined increase of load demand on said secondary element to sa t-' I isfy said load demand. I I 5. A refrigerating machine including a cabinet,

a primary cooling evaporator of the flooded-type for cooling one portion of said cabinet, said evaporator having a vapor collecting header at least a portion of which extends above the normal level of liquid refrigerant in said evaporator,an evaporator of the secondary type including a condensing section arranged inheat exchange relatransferring heat from said secondary evapora tor to said primary evaporator.

7; A refrigerating machine including and provided with a metal liner arranged within.

said cabinet forming aeo-rnpartmentto be cooled, a primary evaporator for cooling an upper portion of said compartment, a secondary evapora ter arranged'on theouter wall of said liner in =-heat conductingrelation ,thercwithfor cooling alower portion of "said compartment. and an intermediate evaporator of the secondary type for transferring h'eatfrom said secondary evaporator to said primaryv evaporator, said interme'diate evaporator having a condensing portionjremovably secured to said primary evaporatorand a vaporizing portion removably secured to said liner adjacent the upper portion of said "secondary evaporator whereby said intermediate evaporator -may be removed from said compartment without disturbing said primary and said secondary evap-.

orators.-

I 8, A refrigerating machineincludinga cabinet and provided with a metal liner arranged therein tionship with said primary evaporator for removing heat from another portion of said cabinet/ temperatureresponsive means including a thermal control element secured in heat exchange re lationship with said header above the normal level of liquid refrigerant in said primary evaporator for controlling the operation of said primary evaporator, and a riser in communication with the condensing section of said secondary element and having its upper end in thermal contact with said thermal element for actuating said controlling means upon the occurrence of a predetermined incrcase of load demand on said secondary element to satisfy the increased load demand.-

and forminga compartment to be coolcd, a pri-,

mary evaporator forjcooling an upper portion of said compartment; means including a" thermal element responsive to the temperature ofsaid primary evaporator for controlling the operation thereof, a secondary evaporator arranged on the outer wall of said liner infheat'conducting relation therewith for cooling a lower portionof saidc j compartment, an intermediate evaporator of the secondary typefor transferring heat from said secondary evaporator to said primary evaporator,

- said intermediate evaporator having a condens ing portion removably secured to' said primaryevaporator and. a vaporizing portion romovably 6. A refrigerating machine including a cabinet having a metal liner providing, a compartment to e be cooled, an evaporatorcof theprimary type for cooling one portion of said cabinet, an evaporator .of the secondary type arranged on said liner for cooling the. air in said compartment, and

means including anintermediate evaporator of c the secondary type removably secured in heat exchange relationship with said primary evaporator and with said secondary evaporator for' secured to, said liner adjacent the upper portionof saidsccondary evaporator whereby said inter mediate evaporator mayi he removed :from said compartment without disturbing said primary and said secondary evaporators'and av riser in cornmunication 'with the condensing portion or. said intermediate evaporator and having its upper end in thermal contact with jsaid, thermal,

element for actuating said temperature responsive means upon the occurrence of a' predetermined increase of load demand on saidsecondary evaporator to satisfy the'increased'load .de-

mand.

a cabinet [CARL H. STEENSTRUP. v 

